FAO Species Identification Guide for Fishery Purposes Western

1030 Lobsters
5a. Medium size (adults more than 12 cm body length); distal margin of antenna with more
than 20 small teeth; exopods of maxillipeds with multiarticulate flagella (Fig. 5) . . . . . . Arctides
(a single species, Arctides regalis, in the area)
5b. Small size (usually less than 10 cm body length); distal margin of antenna with less than
10 large teeth; exopods of maxillipeds without flagellum or with flagellum transformed
to a single laminate segment (Fig. 6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . Scyllarus
(generally, the species of Scyllarus can be separated into 2 groups: 1 has arborescent sculpture on the abdomen
while the other group has broad transverse grooves on the abdomen and lacks an arborescent sculpture)
orbit
shallow
cervical
incision
Fig. 5 Arctides regalis
many small
teeth
carapace
rectangular
arborescent
sculpture
Key to the species of Ibacus occurring in the area
shallow
cervical
incision
carapace
rectangular
Fig. 6 Scyllarus
few large
teeth
orbit
margin
with
many
teeth
arborescent
sculpture
transverse
grooves
abdomen
(Scyllarus rugosus)
1a. Carapace with 6 to 9 posterolateral teeth (Fig. 7a-c) . . . . . . . . . . . . . . . . . . . . . . . → 2
1b. Carapace with more than 9 posterolateral teeth (Fig. 7d-f) . . . . . . . . . . . . . . . . . . . . → 4
2a. Merus of third maxilliped concave on ventral surface and without deep incisions on inner
margin (Fig. 8a); cervical incision very wide (Fig. 7a) . . . . . . . . . . . . . . . . . . Ibacus brucei
2b. Merus of third maxilliped convex on ventral surface and provided with deep incisions on
inner margin (Fig. 8b, c); cervical incision narrow (Fig. 7b, c) . . . . . . . . . . . . . . . . . . .→ 3
3a. Branchial carina nearly straight (Fig. 7b); posterior incision of orbit without tubercle.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ibacus novemdentatus
3b. Branchial carina strongly convex (Fig. 7c); posterior incision of orbit with a distinct
tubercle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ibacus peronii
cervical
incision
wide
branchial carina
straight
7-8
posterolateral
teeth
a) Ibacus brucei b) Ibacus novemdentatus
body heavily
pubescent
12-17
posterolateral
teeth
branchial carina
strongly convex
d) Ibacus brevipes e) Ibacus pubescens f) Ibacus ciliatus
Fig. 7 carapace (dorsal view)
7-8
posterolateral
teeth
11-15
posterolateral
teeth
c) Ibacus peronii
6 or 7
posterolateral
teeth
body naked
10-12
posterolateral
teeth